The present invention relates to a process for cleaning and separating a stream of particle-containing fluid. More particularly, the invention relates to treating such a stream without materially reducing its heat or energy content, or causing significant erosion of stream-splitting components, by flowing the stream into and out of the vortex of a cyclone while adjusting a remotely controllable vortex stabilizer within the cyclone to provide a selected rate of outflow of treated fluid.
Various cyclone separators have been described in patents such as the following: U.S. Pat. No. 3,235,090 describes a cyclone separator for separating dirt particles from dry cleaning fluid. U.S. Pat. No. 3,313,413 describes a cyclone separator for removing particles from paper pulp stock. U.S. Pat. No. 3,489,286 describes a cyclone separator with baffles for preventing the return of the outflowing separated particles. U.S. Pat. No. 3,529,724 describes a cyclone separator with a barrier filter in the particle collecting chamber. U.S. Pat. No. 3,645,401 describes a cyclone separator with baffles mounted in a fixed position below the normal vortex to reduce the centrifugal force and thus reduce the tendency for sticky particles to accrete on walls near the particle-outlet opening. U.S Pat. No. 3,802,570 describes a cyclone separator containing a truncated tube mounted in the lower end of a vortex tube to function as a vortex-stabilizer for centering and stabilizing the vortex near the mouth of the particle outlet. U.S. Pat. No. 4,212,653 describes a cyclone separator containing an inlet near the top of the vortex tube for a co-swirling stream of gas and a near-bottom located vortex stabilizing base plug or vortex shield.
Various reaction processes produce streams of particle-containing fluids which need to be divided, or controlled, or freed of particles in order to recover heat or energy, or provide relatively clean fluid for re-use or further processing. Such situations are commonplace in converting solid, or substantially solid, carbonaceous materials such as coals, tars and lignites, or the like, to synthetic fuels, etc. For example, U.S. Pat. No. 3,963,457 describes a coal gasification process in which cooled and cleaned recycled gas, from which particulate matter, such as vaporized, molten or solid slag or fly ash, have been removed in order to cool the product gas as it leaves the gasifier unit. U.S. Pat. No. 4,054,424 describes a slagging coal gasifier with a similar quenching of the product gas in a quench zone into which a shielding gas is introduced between the product gas and the walls of the vessel. U.S. Pat. No. 4,149,859 describes a process for separating particles from a hot gas, such as that formed during coal gasification, by means of a sequence of cooling and separating steps, to provide both a particle-free gas and a suspension of particles for use in a quenching process.
In view of the prior art, it was previously known to use a cyclone separator arranged for receiving and separating particle-suspending gaseous or liquid fluids. Such separators sometimes used vortex stabilizers to increase the efficiency with which solid or liquid particles were separated by being moved radially outward and downward past the vortex-stabilizer with the stabilizer being located at, or somewhat below, the natural turning point of the vortex. Such a location for a vortex stabilizer was thought to be its best location for its main function of maintaining an adequate downward and outward expulsive force on the separated particles. As far as applicant is aware, it was not previously recognized that a distinctly different and valuable function could be introduced while inflowing and treating a particle-laden fluid in a cyclone separator.
In such a procedure, the length of the vortex can be changed, without necessarily terminating or otherwise changing the rate or pressure at which the inflowing stream is provided. For example, when the vortex length is shortened by moving the vortex-stabilizer closer to the outlet for the particle-depleted fluid, the result is mainly an increase in the pressure-drop across the cyclone. The increased pressure drop increases the back pressure on the inflowing stream and thus can be used to throttle and/or divert the stream of fluid which is flowed through the vortex and out (as a particle-depleted fluid) while causing only a minor reduction in the efficiency with which the suspended particles are separated.